Field of the Invention
This invention relates to the field of chemical operations and more specifically to the field of decontamination of sour water by removing hydrogen sulfide.
Background of the Invention
There has been an increasing need to decontaminate storage tanks such as petroleum refinery storage tanks that contain large volumes of sour water. Such sour water typically contains hydrogen sulfide (H2S). Conventional methods for treating sour water to destroy the H2S include using an oxidizing agent, which typically converts H2S to a variety of non hazardous sulfur compounds.
Conventional oxidizing agents include hydrogen peroxide, potassium permanganate, sodium persulfate, sodium hypochlorite, dimethyldodecylamine-N-oxide, and sodium perborate. Each of such conventional methods has drawbacks. For instance, hydrogen peroxide is typically dangerous because the reaction between H2O2 and H2S may be very exothermic, with the heat of reaction potentially causing a violent eruption of boiling water. Drawbacks to potassium permanganate include that the product of reaction with H2S may be solid manganese dioxide, which is a solid and may add to sludge accumulation in the tank. Further drawbacks to potassium permanganate include that the manganese dioxide may accumulate in a tank in the presence of organics, which may lead to combustion. Drawbacks to sodium persulfate include that the reaction with H2S may be very exothermic and also that its addition to a sulfide-laden water may result in an exotherm, which may cause a rapid rise in temperature. Drawbacks to sodium hypochlorite include that its use may release toxic chlorine gas. Drawbacks to dimethyldodecylamine-N-oxide include that its use may be impractical as it may be added in large quantities to sufficiently destroy the H2S in large volumes of sour water. Drawbacks to sodium perborate include the amounts typically used to sufficiently destroy the H2S may be impractical.
Consequently, there is a need for an improved method for treating H2S in sour water.